Calcium niobate nanosheets: A 2D model system for investigating low energy ion scattering surface and tail signals

We characterize the shape of the surface peaks and subsurface signal in low energy ion scattering (LEIS) spectra of calcium niobate (Ca2Nb3O10) nanosheets and sub-nanometer amorphous Nb-oxide films. By analyzing LEIS spectra acquired at different primary ion energies, we show that channeling effects significantly contribute to the spectral shape of the nanosheet sample. In addition, by depositing Si films of varying thicknesses on the nanosheets, we track the evolution of the Nb signal as a function of depth. Together, these results demonstrate how the crystalline structure of the sample influences the LEIS response. Since common LEIS simulation models do not account for the crystal structure, our findings highlight the importance of understanding the sample’s microstructure prior to simulating LEIS spectra.